Track circuit apparatus



Jan. 8, 1952 R. M. GILSON 2,581,527

TRACK CIRCUIT APPARATUS Filed April e, 1948 IN VEN TOR.

BY M

H16 ATTORNEY Patented Jan. 8, 1952 ,Robert MrGllson; Pittsburgh, Pa., assignor to. westi rh usemirbrah p y, a rmraiqn. Q 5 .B; tragic enri qet eaertfl. t$ r e l 313 2 My invention 7 relates to-track-circuitappara: tus, and more particularly to trackcircuit: an: paratus for governing both waysideand cab. signals.

The present applicationtis a divisioncotmy copending application for Letters Patent of the. United States, Serial No. 636,703, filed December 22, 1945, for Tracie. Circuit. Apparatus,- now. Patent No. 2,515,642, granted J u1-y;18, 1950.

In railwaysignaling the track circuitiof atracksection is supplied in many cases with direct current for energizing-atrack. relaywhen the section is unoccupied. and with alternating, current for operation of a cab,- si al. when .aitrain moves through the section. Thereiarewellder, fined operating. characteristics prescribed for track circuits. and these characteristics are, best metin one manner when directycurrent isaused and in a somewhat difierent; manner wh.en,.,a1ter.- nating current isusedu Also, .when=a;,track cir.- cuit is to be supplied with directgcurrentiforrone function and with alternatingcurrentfor another; function,v it is. in the interest of -econ o ny and simplicity, that a single source; 01 poweris used;

Accordingly, a featuregoi ;my invention isthe prov i n f nov l; and dmnmvcd ee circuit. apparatus for control .ofgbqth. waysiderand .11 cab. signals,

not er ature. r venti n s theme: vision ofimproved trac k circuit apparatus: to supply u r nt fo ner zin rect ur e t tra k relay n fo ne at naa b gnal o a: in sour e fa tern r c re t:

Other e ures,.. biec s.-andtad an ae so my. enti i l a pear s. hat. p cification: DI g 'B fiS- To attain the foregoing features objects tand advantages; ofmy invention, 1; provide a,; novel circuit network for connectingasource of alter n t n ntto he-tra k i u t t supp vcrr rent through; a full waverectif er; for enerizing e-t ackr av; h n. the. sec ion. s unoccupied; and to supply an alternating current for operation of the cab signal when a; train moves through the section,

I shall describettwo, forms of apparatus, em: bodying my invention andshall-thempoint out; the novel features thereof -in claims,

In the accompanying drawings,; Figs.: 1;. and 2, are diagrammatic ViQWSyShQWj-HQ two different. forms of.track;, circuit apparatusi each of: which form of apparatus embodiesrmyi invention.

In each of the twotviews like; reference-characters; are used to designatersimilar parts.

- Referrin to ma, the reference: haracters:-

[wand lb designate the track railsof a railway over which traffic normally moves in the directioniindicated by an arrow, and which rails. are formedwithcatrack section D--E, the section D"-E being ordinarily one section of a series of sections of a signaling system. The rails la and ID are arranged to be includedin a track circuit which. alsoincludes a. track. relay, connected across the rails atone end of thesection and a sourceotlpower: connected across the rails at the other .end .of the section.

As here shown, the track relaytis a direct current track relay DTRI having a winding con.- nected acrosstherails adjacent the, entranceend D ofesection D.E. The power source comprises a track transformer ET32having a primary winding 29randtwo secondary windingsttiand. 3%.

A, portion of secondary winding this connected acrossinput terminals l1 and it. of rectie fier 19,1 the portion of the winding to be used being:- preselected according to the, particular track; section to be. supplied. Theoutput terminalsjdand 2| of rectifier I9 are, connected acrossthe rails by terminal 20 being connected tdrailib through a reactor 38wand-1eadwire 22; and: terminal 21, being connected to rail la through winding 31,,presistor 23; contact lfl of coder- GB and leadwire 21. Acapacitor H is connected around rectifier l9 and reactor 38.

Secondary winding 30 in combination with the rectifier i9 andthecapacitortl which preferably is orjrelatively large capacitance, maintain a unidireetionalyoltage acrossthe capacitor 41 oi the polarityindicated in Fig. 1. Secondary Winding 3| provides an alternatingcurrent component to the track circuit; the path for which includes lead wire 22 from rail lb, capacitor 4|, secondary winding 3|; resistor 26, co'der'contact '43)} and leadwire 21 to rail la. Capacitor M-is thus a inutualelementin the directcurrent and alter ating currentsupply circuits and: acts very inuchdi'l re a battery to provide adirect' voltage inseries withthe'alternating voltage with con sequent directcurrent and alternating current conipgnen ts in the currentrin thefrailsh The direct current component iseffective to iergize thedirect current tracl; relay DTRl, when the sct qe s n ccu ied nd te a n we rent: con ponent serves to operate a cab signal when a train occupies the track section. The reactortflpprevents the alternating current com.- ponentfrom unbalancing the currents between thetwo legs of each pair of legs in rectifier l9 duces the ripple in the rectified voltage supplied by secondary winding 30 and rectifier [9 to capacitor M.

In Fig. 2, secondary winding 30 of transformer ET3 is connected across the outside terminals of rectifiers 8 and 9 in series and poled reverse to each other. The junction terminal of rectifiers 8 and 9 is connected to rail Ia through resistor 25, coder contact 40 and lead wire 21, and a mid terminal of winding 30 is connected to rail lb through reactor 38 and lead wire 22. Thus a full wave rectified current is supplied to the track circuit from secondary winding 30 and such current is available to energize track relay. DTRI- when the section is unoccupied. r

Secondary winding 3| is connected across the track rails through capacitor 4!, back contact 42 of approach controlled relay VR and resistor26.

Thus when relay VB is released an alternating current i supplied to the rails from secondary winding 3| and such current is available to operate a cab signal when a train occupies the section. The capacitor 4| serves to block the direct current from winding 30, and the. reactor 38 serves to prevent the alternating current from unbalancing the rectifiers. Thus in Fig., 2, the direct current component and the alternating current component of the current in the rails can be independently adjusted.

It is obvious that an approach controlled relay VR can be provided in the connection of secondary winding 3| of Fig. 1 to the rails and the alternating current component of the rail current for operation of cab signals supplied only when the section is occupied and my invention contemplates such a modification of Fig. l.

Track circuit apparatussuch as here disclosed has the advantages that froma single source of alternating current a track circuit is provided at times with a rectified direct current having a relatively small alternating current component for energization of a direct current track relay, and at other times with a current having a relatively large alternating current component for operation of cab signals-this latter current also having a direct current component effective to initially energize the track relay.

Although I have herein shown and described but two forms of track circuit apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In a track circuit for a track section through which trafiic moves in a given direction, the combination comprising, a direct current track relay connected across the rails at the entrance end of the section, a transformerhaving a primary winding and a first and a second secondary wind ing, said primary winding connected to a source of alternating current, a reactor having inductance, a full wave rectifier; a first circuit including m series said first secondary winding, said rectifier and said reactor and connected across the rails at the exit end of the section to supply a full wave rectified current for energizing said track relay when the section is unoccupied; an

impedance device, a second circuit including in series said second secondary winding and said impedance device and connected across the rails at the exit end of the section to supplyan alter-- nating current which is available for operating a cab signal when a train moves through the section, said reactor disposed in said first circuit with respect to said rectifier to substantially block the alternating current of the second circuit from unbalancing said rectifier, and said impedance device disposed adjacent said second secondary winding to minimize the flow of said rectified current through the second secondary winding.

2. In combination, a track section formed with a track circuit including the track rails and a direct current track relay connected across the rails at the entrance end of the section, a track transformer having a primary winding receiving an alternating current, two half wave rectifiers connected in -series and poled reverse to each other across a first secondary winding of said transformer, said rectifier having their junction terminal connected through a resistor to one railatthe exit end of the section and said first secondary winding having a mid terminal connected through a reactor to the other rail at the exit end of the section to. supply full wave rectified current to energize said track relay, an approach controlled relay for said section, and means including a contact of said approach controlled relay and a capacitor to connect a second secondary winding of said transformer to the rails at theexit end of the section to at times supply an alternating current to the rails to operate a cab signal of a train traversing said section.

3. In a track circuit for a track section through which traflic moves in a given direction, the combination comprising, a direct current track relay connected across the rails at the entrance end of the section, a transformer having a primary winding and a first and a second secondary winding, said primary winding being connected to an alternating current source, a full wave rectifier, an inductance device; a first circuit means including said first secondary winding, said rectifier and said inductance device connected across the rails at the exit end of the section to supply a full wave rectified current for energizing said track relay; a second circuit means to connect said second secondary" winding across the rails at the exit end of the section to supply an alternating current which is available for operating a cab signal of a train moving through the section, said inductance device disposed with respect to said rectifier to substantially block the flow of alternating current from the second circuit means in said rectifier, and an impedance interposed in said second'circuit means adjacent said second secondary'winding to minimize the flow of the rectified current from said first circuit means in said second secondary winding. r

4. In a track circuit for a track section through which trafiic moves in a given direction, the combination comprising, adirect current track'relay connected acrossthe-rails at the entrance end rectifier and said inductance device having con nections across the rails at the exit end of the section to supply full wave rectified current for energizing said track relay; a second circuit including said second secondary winding and said impedance having connections across the'rails at the exit end of the section to supply an alter-- nating current which is available foreoperating a cab signal when a train moves through the section, and said first and second circuits disposed in parallel for said inductance device to substantially block the flow of the alternating current supplied to the rails from unbalancing said rectifier and for said impedance to substantially block the flow of the rectified current supplied to the rails from flowing in said second secondary winding.

ROBERT M. GILSON.

The fol file of this patent:

Number UNITED STATES PKTENTS Name Date Nicholson June 30, 1936 Martin Mar. 29, 1949 

